Wireless access system using multiple modulation formats in TDD frames and method of operation

• US 20020136168A1
• Filed: 04/20/2001
• Published: 09/26/2002
• Est. Priority Date: 01/19/2001
• Status: Active Grant

• Current Assignee: Access Solutions, Ltd. (LOXAM SAS)
• Original Assignee: Access Solutions, Ltd. (LOXAM SAS)
• Inventors: McKown, Russell C., Struhsaker, Paul F., Nelson, Robert R.
• Granted Patent: US 7,173,916 B2
• Time in Patent Office: Days
• US Class Current: 370/277
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/1825 Adaptation of specific ARQ protocol parameters according to transmission conditions
• CPC Class Codes: H04L 5/0005 Time-frequency

Abstract

There is disclosed a radio frequency (RF) modem shelf for use in a fixed wireless access network comprising a plurality of base stations capable of bidirectional time division duplex (TDD) communication with wireless access devices disposed at a plurality of subscriber premises. The radio frequency (RF) modem shelf comprises: a) a first RF modem for communicating with a plurality of the wireless access devices using TDD frames, each TDD frame having an uplink for receiving data and a downlink for transmitting data; and b) a modulation controller associated with the RF modem shelf for determining an optimum modulation configuration for each of the plurality of wireless access devices communicating with the first RF modem. The modulation controller causes the first RF modem to transmit downlink data to a first wireless access device in a first data block having a first optimum modulation configuration and to transmit downlink data to a second wireless access device in a second data block having a different second optimum modulation configuration.

Claims

1. For use in a fixed wireless access network comprising a plurality of base stations capable of bidirectional time division duplex (TDD) communication with wireless access devices disposed at a plurality of subscriber premises, a radio frequency (RF) modem shelf comprising:

a first RF modem capable of communicating with a plurality of said wireless access devices using TDD frames, each TDD frame having an uplink for receiving data and a downlink for transmitting data; and

a modulation controller associated with said RF modem shelf capable of determining an optimum modulation configuration for each of said plurality of wireless access devices communicating with said first RF modem, wherein said modulation controller causes said first RF modem to transmit downlink data to a first wireless access device in a first data block having a first optimum modulation configuration and to transmit downlink data to a second wireless access device in a second data block having a different second optimum modulation configuration.

2. The RF modem shelf as set forth in claim 1 wherein said modulation controller determines said first and second optimum modulation configurations based on channel conditions associated with channels used to communicate with said first and second wireless access devices.

3. The RF modem shelf as set forth in claim 2 wherein said first modulation configuration comprises a first modulation format and said second modulation configuration comprises a different second modulation format.

4. The RF modem shelf as set forth in claim 3 wherein said second modulation format is more complex than said first modulation format if channel conditions associated with a first channel used to communicate with said first wireless access device are noisier than channel conditions associated with a second channel used to communicate with said second wireless access device.

5. The RF modem shelf as set forth in claim 4 wherein said first and second modulation formats comprise one of binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), and 16 quadrature amplitude modulation (QAM).

6. The RF modem shelf as set forth in claim 3 wherein said first modulation configuration comprises a first forward error correction code level and said second modulation configuration comprises a different second forward error correction code level.

7. The RF modem shelf as set forth in claim 6 wherein said first error correction code level is more complex than said second error correction code level if channel conditions associated with a first channel used to communicate with said first wireless access device are noisier than channel conditions associated with a second channel used to communicate with said second wireless access device.

8. The RF modem shelf as set forth in claim 2 wherein said first modulation configuration comprises a first physical beam forming technique and said second modulation configuration comprises a different second physical beam forming technique.

9. A fixed wireless access network comprising:

a plurality of base stations capable of bidirectional time division duplex (TDD) communication with wireless access devices disposed at a plurality of subscriber premises; and

a radio frequency (RF) modem shelf comprising;

a first RF modem capable of communicating with a plurality of said wireless access devices using TDD frames, each TDD frame having an uplink for receiving data and a downlink for transmitting data; and

a modulation controller associated with said RF modem shelf capable of determining an optimum modulation configuration for each of said plurality of wireless access devices communicating with said first RF modem, wherein said modulation controller causes said first RF modem to transmit downlink data to a first wireless access device in a first data block having a first optimum modulation configuration and to transmit downlink data to a second wireless access device in a second data block having a different second optimum modulation configuration.

10. The fixed wireless access network as set forth in claim 9 wherein said modulation controller determines said first and second optimum modulation configurations based on channel conditions associated with channels used to communicate with said first and second wireless access devices.

11. The fixed wireless access network as set forth in claim 10 wherein said first modulation configuration comprises a first modulation format and said second modulation configuration comprises a different second modulation format.

12. The fixed wireless access network as set forth in claim 11 wherein said second modulation format is more complex than said first modulation format if channel conditions associated with a first channel used to communicate with said first wireless access device are noisier than channel conditions associated with a second channel used to communicate with said second wireless access device.

13. The fixed wireless access network as set forth in claim 12 wherein said first and second modulation formats comprise one of binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), and 16 quadrature amplitude modulation (QAM).

14. The fixed wireless access network as set forth in claim 10 wherein said first modulation configuration comprises a first forward error correction code level and said second modulation configuration comprises a different second forward error correction code level.

15. The fixed wireless access network as set forth in claim 14 wherein said first error correction code level is more complex than said second error correction code level if channel conditions associated with a first channel used to communicate with said first wireless access device are noisier than channel conditions associated with a second channel used to communicate with said second wireless access device.

16. The fixed wireless access network set forth in claim 10 wherein said first modulation configuration comprises a first physical beam forming technique and said second modulation configuration comprises a different second physical beam forming technique.